﻿/* 
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System;
using System.Text;
using Lucene.Net.Index;
using Lucene.Net.Store;
using Lucene.Net.Util;

namespace Lucene.Net.Search
{
    /// <summary>
    /// Regular expression based query.
    /// </summary>
    /// <remarks>http://www.java2s.com/Open-Source/Java-Document/Net/lucene-connector/org/apache/lucene/search/regex/RegexQuery.java.htm</remarks>
    public sealed class RegexQuery : MultiTermQuery, IEquatable<RegexQuery>
    {
        private readonly System.Text.RegularExpressions.Regex _regex;
        public Term Term { get; }

        public RegexQuery(Term term, System.Text.RegularExpressions.Regex regex)
        {
            Term = term;
            _regex = regex;
        }

        /// <summary>Construct the enumeration to be used, expanding the pattern term. </summary>
        protected override FilteredTermEnum GetEnum(IndexReader reader, IState state)
        {
            return new RegexTermEnum(reader, Term, state, _regex);
        }

        public override string ToString(string field)
        {
            StringBuilder buffer = new();
            if (Term.Field.Equals(field) == false)
            {
                buffer.Append(Term.Field);
                buffer.Append(":");
            }
            buffer.Append(Term.Text);
            buffer.Append(ToStringUtils.Boost(Boost));
            return buffer.ToString();
        }

        /// <summary>
        /// Indicates whether the current object is equal to another object of the same type.
        /// </summary>
        /// <returns>
        /// true if the current object is equal to the <paramref name="other"/> parameter; otherwise, false.
        /// </returns>
        /// <param name="other">An object to compare with this object</param>
        public bool Equals(RegexQuery other)
        {
            if (other == null)
                return false;
            if (this == other)
                return true;

            if (base.Equals(other) == false)
                return false;
            return Term.Equals(other.Term);
        }

        public override bool Equals(object obj)
        {
            if ((obj == null) || (obj as RegexQuery == null))
                return false;
            if (this == obj)
                return true;

            return Equals((RegexQuery)obj);
        }

        public override int GetHashCode()
        {
            return 29 * base.GetHashCode() + Term.GetHashCode();
        }
    }
}
